696. Cefiderocol Susceptibility Against Molecularly Characterized Carbapenemase-Producing Gram-Negative Bacteria in North America and Europe Between 2014 and 2017: SIDERO-WT-2014 to -2016 Studies

BACKGROUND: Antibiotic susceptibility surveillance is the foundation for selecting treatment options as well as immediate and long-term strategies for combating antimicrobial resistance. We have conducted three surveillance studies SIDERO-WT-2014/-2015/-2016 with approximately 30,000 Gram-negative strains isolated in North America and Europe between 2014 and 2017. Here, we present the latest data of molecular analysis on acquired carbapenemase genes and antibiotic susceptibility of 3691 meropenem-nonsusceptible strains in the surveillance studies. METHODS: Meropenem-nonsusceptible strains isolated in North America (n = 1009) and Europe (n = 2,682), consisting of 1,897 Acinetobacter baumannii, 1,154 Pseudomonas aeruginosa, 447 Klebsiella pneumoniae, and 193 other Enterobacteriaceae were tested. Conventional PCR was used to detect known carbapenemases. Cefiderocol MICs were determined by broth microdilution method using iron-depleted cation-adjusted Mueller–Hinton broth. RESULTS: The percentages of known carbapenemases detected in 3 main pathogens are shown in the Table. In A. baumannii complex, OXA-23 was predominant followed by OXA-24 in most countries. The detection rates of VIM in P. aeruginosa were ≥40% in Greece and Russia, but none of the strains in the United States carried VIM. In K. pneumoniae, the predominant carbapenemase varied among the countries, with KPC predominating in the USA, Greece and Italy, while OXA-48-like was dominant in Russia, Spain and Turkey. Cefiderocol MIC(90) were ≤4 μg/mL against these 3 pathogens in all 6 countries, except for A. baumannii strains in Russia. CONCLUSION: Carbapenemase detection rates, especially in P. aeruginosa and K. pneumoniae, were quite different among the countries. Cefiderocol demonstrated potent in vitro activity against meropenem-nonsusceptible strains irrespective of the presence of specific carbapenemases. [Image: see text] DISCLOSURES: All authors: No reported disclosures.